Balloon catheter

ABSTRACT

Balloon catheter includes an outer shaft having a hypotube and a monolithic single-layer distal outer member, a balloon in fluid communication with an inflation lumen, and a monolithic inner tubular member having a guidewire lumen defined therethrough. The outer shaft has the inflation lumen defined therethrough. The monolithic single-layer distal outer member is necked to a reduced diameter along an entire length thereof. A proximal end of the monolithic single-layer distal outer member is coupled to the hypotube. A distal section of the hypotube comprises a skive defined by a first angled cut, an axial cut, and a second angled cut. The balloon has a proximal balloon shaft coupled to a distal end of the monolithic single-layer distal outer member. The monolithic inner tubular member extends distally from a proximal port in the monolithic single-layer distal outer member through the balloon to form a tip.

REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/046,157, filed on Sep. 4, 2014, and U.S. Provisional PatentApplication No. 62/163,839, filed on May 19, 2015, the contents of eachof which is hereby incorporated by reference in its entirety.

BACKGROUND

Field of the Disclosed Subject Matter

The disclosed subject matter relates to medical devices, for example toballoon catheters for use in angioplasty and/or stent or scaffolddelivery.

Description of Related Art

In percutaneous transluminal coronary angioplasty (PTCA) procedures, aguiding catheter is advanced in the vasculature of a patient until thedistal tip of the guiding catheter is seated in a desired coronaryartery. A guidewire is advanced out of the distal end of the guidingcatheter into the coronary artery until the distal end of the guidewirecrosses a lesion to be dilated. A dilatation catheter, having aninflatable balloon on the distal portion thereof, is advanced into thecoronary anatomy over the previously introduced guidewire until theballoon of the dilatation catheter is positioned across the lesion. Oncepositioned, the dilatation balloon is inflated with inflation fluid oneor more times to a predetermined size at a suitable pressure to compressthe stenosis against the arterial wall to open up the vascularpassageway. Generally, the inflated diameter of the balloon isapproximately the same diameter as the native diameter of the body lumenbeing dilated to complete the dilatation but not over expand the arterywall. After the balloon is deflated, blood resumes flowing through thedilated artery and the dilatation catheter and the guidewire can beremoved therefrom.

In such angioplasty procedures, there may be restenosis of the artery,i.e., reformation of the arterial blockage, which necessitates eitheranother angioplasty procedure, or some other method of repairing orstrengthening the dilated area. To reduce the restenosis rate and tostrengthen the dilated area, physicians may additionally oralternatively implant an intravascular prosthesis inside the artery atthe site of the lesion. Such stents or scaffolds may be bare metal,polymeric, or coated with a drug or other therapeutic agent. Stents orscaffolds may also be used to repair vessels having an intimal flap ordissection or to generally strengthen a weakened section of a vessel.Stents or scaffolds are usually delivered to a desired location within acoronary artery in a contracted condition on a balloon of a catheterwhich is similar in many respects to a balloon angioplasty catheter andexpanded to a larger diameter by expansion of the balloon. The balloonis deflated to remove the catheter with the stent implanted within theartery at the site of the dilated lesion. Coverings on an inner or anouter surface of the stent have been used in, for example, the treatmentof pseudo-aneurysms and perforated arteries, and to prevent prolapse ofplaque. Similarly, vascular grafts comprising cylindrical tubes madefrom tissue or synthetic materials such as polyester, expandedpolytetrafluoroethylene, and DACRON® may be implanted in vessels tostrengthen or repair the vessel, or used in an anastomosis procedure toconnect vessels segments together. For details of example stents, seefor example, U.S. Pat. No. 5,507,768 to Lau, et al. and U.S. Pat. No.5,458,615 to Klemm, et al., the contents of each of which areincorporated herein by reference in their entireties.

In addition to percutaneous transluminal angioplasty (PTA), PTCA, andatherectomy procedures, balloon catheters are also used to treat theperipheral system such as in the veins system or the like. For instance,a balloon catheter is initially advanced over a guidewire to positionthe balloon adjacent a stenotic lesion. Once in place, the balloon isthen inflated, and the restriction of the vessel is opened, and a stentor scaffold can be delivered if desired. Likewise, balloon catheters arealso used for treatment of other luminal systems throughout the body.

Typically, balloon catheters comprise a hollow catheter shaft with aballoon secured at a distal end. The interior of the balloon is in afluid flow relation with an inflation lumen extending along a length ofthe shaft. Fluid under pressure can thereby be supplied to the interiorof the balloon through the inflation lumen. To position the balloon atthe stenosed region, the catheter shaft is designed in multiple parts tohave suitable pushability (i.e., the ability to transmit force along thelength of the catheter), trackability, and flexibility, to be readilyadvanceable within the tortuous anatomy of the vasculature. The catheteris also designed so that it can be withdrawn from the patient afterdelivery. Conventional balloon catheters for intravascular procedures,such as angioplasty and stent delivery, frequently have a relativelystiff proximal shaft section to facilitate advancement of the catheterwithin the body lumen, a mid-shaft section of an intermediate (ortransition) flexibility, and a relatively flexible distal shaft sectionto facilitate passage through tortuous anatomy, such as distal coronaryand neurological arteries, without damage to the vessel wall or damageto the stent, in the case of stent delivery.

Traditional catheter shafts are often constructed with inner and outermember tubing with an annular space therebetween for balloon inflation.In the design of catheter shafts, it is desirable to predetermine orcontrol characteristics such as strength, stiffness and flexibility ofvarious sections of the catheter shaft to provide desired catheterperformance. This is conventionally performed by combining separatelengths of tubular members of different material and/or dimensions andthen assembling the separate members into a single shaft length.However, the transition between sections of different stiffness ormaterial can be a cause of undesirable kinking along the length of thecatheter. Such kinking is particularly evident in rapid exchange (RX)catheters, wherein the proximal shaft section does not include theadditional structure of a guidewire lumen tube. For example, aconventional RX catheter generally consists of a proximal hypotubehaving a single inflation lumen therethrough, a mid-shaft transitionsection, and a dual lumen or coaxial tube configuration at a distal endsection having both a guidewire lumen and an inflation lumen therein.Known techniques to minimize kinking at the transition between the morerigid proximal section and the more flexible distal section includebonding two or more segments of materials having different flexibilitytogether to form the shaft. Such transition bonds need to besufficiently strong to withstand the pulling and pushing forces on theshaft during use.

To address the described issues, catheters having varied flexibilityand/or stiffness have been developed with various sections of thecatheter shaft that are specifically tailored to provide desiredcatheter performance. For example, each of U.S. Pat. No. 4,782,834 toMaguire and U.S. Pat. No. 5,370,655 to Burns discloses a catheter havingsections along its length which are formed from materials having adifferent stiffness; U.S. Pat. No. 4,976,690 to Solar discloses acatheter having an intermediate waist portion which provides increasedflexibility along the catheter shaft; U.S. Pat. No. 5,423,754 toCornelius discloses a catheter having a greater flexibility at itsdistal portion due to both a material and dimensional transition in theshaft; U.S. Pat. No. 5,649,909 to Cornelius discloses a catheter havinga proximal portion with greater stiffness due to the application of apolymeric coating thereto; and U.S. Pat. No. 8,444,608 to Haslingerdiscloses a multilayer catheter shaft using a combination of a highShore D durometer value material and a lower Shore D durometer valuematerial to reduce kinking, the contents of each of which areincorporated herein by reference in their entireties.

However, one difficulty has been balancing the often competingcharacteristics of strength and flexibility of the catheter shaft. Inaddition, use of multiple shaft sections can be a cause of undesirablekinking along the length of the catheter, and the bonds between thesections can be a location of failure (e.g., rupture) if any defects inthe bonds exist.

As such, there remains a need for a catheter having a shaft with animproved combination of characteristics such as strength, flexibility,ease of manufacture, and lower cost. There is also a need for a catheterthat has improved trackability to facilitate further passage throughtortuous anatomy, such as distal coronary arteries, while maintainingthe ability to withdraw from the tortuous anatomy without failure.

SUMMARY

The purpose and advantages of the disclosed subject matter will be setforth in and apparent from the description that follows, as well as willbe learned by practice of the disclosed subject matter. Additionaladvantages of the disclosed subject matter will be realized and attainedby the methods and systems particularly pointed out in the writtendescription and claims hereof, as well as from the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the disclosed subject matter, as embodied and broadly described, thedisclosed subject matter includes balloon catheters and methods ofmaking a balloon catheter. An exemplary balloon catheter includes anouter shaft including a hypotube and a monolithic single-layer distalouter member. The outer shaft has an inflation lumen definedtherethrough. The monolithic single-layer distal outer member is neckedto a reduced diameter along an entire length thereof, and a proximal endof the monolithic single-layer distal outer member is coupled to thehypotube. A distal section of the hypotube comprises a skive defined bya first angled cut, an axial cut, and a second angled cut. The ballooncatheter also includes a balloon in fluid communication with theinflation lumen. The balloon has a proximal balloon shaft coupled to adistal end of the monolithic single-layer distal outer member. Theballoon catheter also includes a monolithic inner tubular member havinga guidewire lumen defined therethrough. The monolithic inner tubularmember extends distally from a proximal port in the monolithicsingle-layer distal outer member through the balloon to form a tip.

In some embodiments, the balloon further comprises a distal balloonshaft having an inner diameter. The distal balloon shaft can have adistal seal portion coupled to the monolithic inner tubular member and aproximal portion free of attachment to the monolithic inner tubularmember. The length of the proximal portion of the distal balloon shaftcan be at least about two times the inner diameter of the distal balloonshaft.

In some embodiments, the monolithic single-layer distal outer membercomprises polyether block amide. The polyether block amide can have aShore durometer hardness of about 63 D to about 72 D, for example about72 D.

In some embodiments, the reduced diameter comprises a first reducedouter diameter and a first reduced inner diameter along a proximalportion of the monolithic single-layer distal outer member and a secondreduced outer diameter and a second reduced inner diameter along thedistal end of the monolithic single-layer distal outer member. The firstreduced outer diameter can be about 0.038 inches to about 0.039 inches,the first reduced inner diameter can be about 0.029 inches to about0.0295 inches, the second reduced outer diameter can be about 0.034inches to about 0.035 inches, and the second reduced inner diameter canbe about 0.029 inches to about 0.0295 inches. The length of the distalend of the monolithic single-layer distal outer member is about 1.0 mmto about 1.2 mm.

In some embodiments, the first angled cut of the skive can have a lengthof about 100 mm, the axial cut can have a length of about 25 mm, and thesecond angled cut can have a length of about 25 mm. The axial cut canhave a height of about 0.0065 inches to about 0.0075 inches. The secondangled cut can define a distal edge height of about 0.0035 inches toabout 0.0045 inches. A proximal section of the hypotube can have anouter diameter of about 0.0275 inches to about 0.0285 inches and aninner diameter of about 0.0195 inches to about 0.0205 inches.

In some embodiments, a scaffold is mounted on the balloon. The scaffoldcan be bioresorbable.

According to another aspect of the disclosed subject matter, methods ofmaking a balloon catheter are provided. An exemplary method includesnecking a tubular member to form a monolithic single-layer distal outermember necked along an entire length thereof, providing a hypotube,coupling a proximal end of the monolithic single-layer distal outermember to the hypotube to form an outer shaft having an inflation lumendefined therethrough, and providing a balloon in fluid communicationwith the inflation lumen. The balloon has a proximal balloon shaft. Themethod also includes coupling the proximal balloon shaft to a distal endof the monolithic single-layer distal outer member and providing amonolithic inner tubular member having a guidewire lumen definedtherethrough. The monolithic inner tubular member extends distally froma proximal port in the monolithic single-layer distal outer memberthrough the balloon to form a tip.

In some embodiments, the balloon further comprises a distal balloonshaft having an inner diameter. The method can include coupling a distalseal portion of the distal balloon shaft to the monolithic inner tubularmember and allowing a proximal portion of the distal balloon shaft to befree of attachment to the monolithic inner tubular member. The length ofthe proximal portion of the distal balloon shaft can be at least abouttwo times the inner diameter of the distal balloon shaft.

In some embodiments, the tubular member is necked from a first outerdiameter of about 0.045 inches to a first reduced outer diameter ofabout 0.038 inches to about 0.039 inches and from a first inner diameterof about 0.033 inches to a first reduced inner diameter of about 0.029inches to about 0.0295 inches along a proximal portion of the monolithicsingle-layer distal outer member. The tubular member can be necked froma first outer diameter of about 0.045 inches to a second reduced outerdiameter of about 0.034 inches to about 0.035 inches and from a firstinner diameter of about 0.033 inches to a second reduced inner diameterof about 0.029 inches to about 0.0295 inches along the distal end of themonolithic single-layer distal outer member. The length of the distalend of the monolithic single-layer distal outer member can be about 1.0mm to about 1.2 mm.

In some embodiments, the method can also include mounting abioresorbable scaffold on the balloon and/or any of the featuresdescribed herein above for the balloon catheter.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and are intended toprovide further explanation of the disclosed subject matter claimed.

The accompanying drawings, which are incorporated in and constitute partof this specification, are included to illustrate and provide a furtherunderstanding of the disclosed subject matter. Together with thedescription, the drawings serve to explain the principles of thedisclosed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view, partially in section, of a balloon catheterembodying features of the disclosed subject matter.

FIG. 2 is a detailed side cross section of the proximal port, includingthe skived distal end of the hypotube disposed within the inflationlumen of the distal outer member.

FIG. 3A is a detailed perspective view of the skive at the distalsection of the hypotube according to embodiments of the disclosedsubject matter.

FIG. 3B is a cross section of the skive of the hypotube at section 3B-3Bin FIG. 3A.

FIGS. 4, 5, 6, and 7 are transverse cross sectional schematic views ofthe balloon catheter shown in FIG. 2, taken along lines 4-4, 5-5, 6-6,and 7-7, respectively.

FIGS. 8 and 9 are transverse cross sectional schematic views of theballoon catheter shown in FIG. 1, taken along lines 8-8 and 9-9,respectively.

FIGS. 10A and 10B are schematic views of the cross section of the distalshaft section according to embodiments the disclosed subject matter.

FIG. 11 is a partial cross-sectional view of an exemplary distal outermember prior to and after a necking process according to embodiments ofthe disclosed subject matter.

FIG. 12 is a partial side view of an inner tubular member and a balloonaccording to exemplary embodiments of the disclosed subject matter.

DESCRIPTION

Reference will now be made in detail to the various exemplaryembodiments of the disclosed subject matter, exemplary embodiments ofwhich are illustrated in the accompanying drawings. The structure andmethod of making the disclosed subject matter will be described inconjunction with the detailed description of the balloon catheter.

In accordance the disclosed subject matter, a balloon catheter isprovided. The balloon catheter includes an outer shaft including ahypotube and a monolithic single-layer distal outer member. The outershaft has an inflation lumen defined therethrough. The monolithicsingle-layer distal outer member is necked to a reduced diameter alongan entire length thereof, and a proximal end of the monolithicsingle-layer distal outer member is coupled to the hypotube. A distalsection of the hypotube comprises a skive defined by a first angled cut,an axial cut, and a second angled cut. The balloon catheter alsoincludes a balloon in fluid communication with the inflation lumen. Theballoon has a proximal balloon shaft coupled to a distal end of themonolithic single-layer distal outer member. The balloon catheter alsoincludes a monolithic inner tubular member having a guidewire lumendefined therethrough. The inner tubular member extends distally from aproximal port in the monolithic single-layer distal outer member throughthe balloon to form a tip.

The accompanying figures, where like reference numerals refer toidentical or functionally similar elements throughout the separateviews, serve to further illustrate various embodiments and to explainvarious principles and advantages all in accordance with the disclosedsubject matter. For purpose of explanation and illustration, exemplaryembodiments of the balloon catheter, and method of making thereof, inaccordance with the disclosed subject matter are shown in FIGS. 1-12.While the present disclosed subject matter is described with respect tocoronary indications, one skilled in the art will recognize that thedisclosed subject matter is not limited to the illustrative embodiments,and that the product and methods described herein can be used in anysuitable application.

For purpose of illustration, and not limitation, reference is made to anexemplary embodiment of a rapid exchange balloon dilatation catheter 100shown in FIGS. 1-12. As shown in FIG. 1, the balloon catheter 100generally comprises an elongated catheter shaft 110 having a proximalshaft section 120 and a distal shaft section 130. The catheter shaft 110can have a variety of suitable configurations. For example, asillustrated in FIG. 1, an outer shaft of the elongate catheter shaft 110can include a hypotube 220 and a monolithic single-layer distal outermember 230. The outer shaft including hypotube 220 and monolithicsingle-layer distal outer member 230 has an inflation lumen 200, 201,202 defined therethrough, and the balloon catheter 100 includes aballoon 140 in fluid communication with the inflation lumen 200, 201,202. The balloon catheter also includes a monolithic inner tubularmember 240 having a guidewire lumen 210, 211 defined therethrough. Themonolithic inner tubular member 240 extends distally from a proximalguidewire port 280 (shown FIG. 2) in the monolithic single-layer distalouter member 230 through the balloon 140 to from a tip 270.

As depicted in FIGS. 1 and 2 for illustration, a proximal end 231 of themonolithic single-layer distal outer member 230 is coupled to thehypotube 220. The distal end 232 of the monolithic single-layer distalouter member 230 is coupled to a proximal balloon shaft 145 of theballoon 140 (as described below). Accordingly, the single-layer distalouter member 230 is a monolithic construction that extends distally fromthe hypotube 220 to the balloon 140. By contrast, typical ballooncatheters include a separate midshaft portion bonded to the hypotube onone end and a separate distal outer shaft on the other end at a mid-lapseal. The monolithic construction of distal outer member 230, inaccordance with the disclosed subject matter, thus provides a jointlessouter member extending from the hypotube all the way to the proximalballoon seal and eliminates the mid lap-seal, which is one potentiallocation of failure in known balloon catheters. The monolithicconstruction of distal outer member 230, in accordance with thedisclosed subject matter, can provide a simpler design, easier and lessexpensive manufacturing, and less parts.

As embodied herein, the distal outer member 230 can comprise anysuitable material. For example, the material can be a polyether blockamide, commercially available under the trade name PEBAX®. The polyetherblock can have any suitable hardness, for example a Shore durometerhardness of about 63 D to about 72 D, preferably about 72 D.Alternatively, nylons can be used alone or in combination (e.g.,blended) with polyether block amide. While described herein asmonolithic single layer distal outer member 230, alternatively amultilayer monolithic construction can be used. In one embodiment, afirst layer can comprise polyether block amide and the second layercomprise nylon. Alternatively, first and second layers can both comprisepolyether block amide or nylon.

In accordance with the disclosed subject matter, the monolithicsingle-layer distal outer member 230 can be necked to a reduced diameteralong an entire length thereof. In some embodiments, the distal outermember 230 can be necked by placing an extruded tube in a neckingmachine, as is known in the art. For example, the necking machine canuse a heated die traversing along the length of the extruded tube havinga mandrel therein to reduce the diameter of the distal outer member 230,as shown in FIG. 11 for the purpose of illustration and not limitation.The outer diameter of the tube can be controlled by the size of the dieand the inner diameter of the tube can be controlled by the diameter ofthe mandrel. After necking, the necked tube can be stabilized at 125° C.for about 10 minutes.

In some embodiments, the diameter of the tube as extruded can be reducedfrom an outer diameter (“OD”) of about 0.045 inch (1101 in FIG. 11) andan inner diameter (“ID”) of about 0.033 inch (1102) to a reduceddiameter of about 0.038 inch to about 0.039 inch OD (1111) and about0.029 inch to about 0.0295 ID (1112) via necking. Thus, the double wallthickness of the necked tubing is about 0.01 inches. In someembodiments, the reduced diameter comprises a first reduced outerdiameter and a first reduced inner diameter along a proximal portion 233of the monolithic single-layer distal outer member and a second reducedouter diameter and a second reduced inner diameter along the distal end232 of the monolithic single-layer distal outer member. For example, thefirst reduced outer diameter can be about 0.038 inches to about 0.039inches, the first reduced inner diameter can be about 0.029 inches toabout 0.0295 inches, the second reduced outer diameter can be about0.034 inches to about 0.035 inches, and the second reduced innerdiameter can be about 0.029 inches to about 0.0295 inches. The length ofthe distal end 232 of the monolithic single-layer distal outer membercan be about 1.0 mm to about 1.2 mm.

In accordance with the disclosed subject matter, necking the distalouter member 230 can provide for more precise dimensions and decreasedtolerances, can impart shear on the material, and can introduce partialorientation in the polymer material, which can increase the strength ofthe distal outer member without significantly effecting flexibility andprovide for increased scaffold push. For example, it is desired for therupture strength of the catheter shaft 110 to be greater than that ofthe balloon 140. As embodied herein, for example, the burst pressure ofthe necked distal outer member 230 can be significantly greater than(e.g., about 4 atm more than, or about 20% more than) that of theballoon 140. Also, introduction of partial (e.g., linear) orientation inthe polymer material of the distal outer member can provide more columnstrength, more push, and can still allow for some play (e.g., stretchingor elongating) during withdrawal from the tortuous anatomy and decreasethe likelihood of rupture or separation as compared to a shaft made of afully oriented polymer material (e.g., blown). Furthermore, having thedistal end 232 of distal outer member 230 necked to a smaller diameterthan the rest of the distal outer member 230 allows the proximal balloonshaft 145 to more easily fit over the distal outer member 230 for heatbonding to a reduce profile (as described below).

As embodied herein, the guidewire lumen 210, 211 can be defined by themonolithic inner tubular member 240 extending from the proximal port 280through the monolithic single-layer distal outer member 230. The spacebetween the monolithic single-layer distal outer member 230 and themonolithic inner tubular member 240 can define inflation lumen 202 influid communication with the inflation lumen 201. Thus, a coaxialannular configuration with the monolithic inner tubular member 240positioned within the monolithic single-layer distal outer member 230can be provided. Alternatively, the monolithic single-layer distal outermember 230 can be formed as a dual lumen member with the guidewire lumenand the inflation lumen defined therein.

For purpose of illustration and not limitation, FIG. 8 is across-section of the catheter 100 of FIG. 1 along the lines 8-8. Asdepicted in FIGS. 1 and 8, the inflation lumen 202 of the monolithicsingle-layer distal outer member 230 includes an annular configuration.The inflation lumen 202 is defined by the annular space between theinterior surface of monolithic single-layer distal outer member 230 andthe exterior surface of the monolithic inner tubular member 240,although a variety of suitable shaft configurations can alternatively beused including non-coaxial and multi-lumen extrusions. The transitionfrom the circular to crescent to annular shape of the inflation lumens200, 201, 202 allows for smooth flow without significant back pressureor resistance.

As embodied herein, the hypotube 220 can be a single lumen hypotube orsimilar tubular member of suitable rigidity and pushability. Forexample, the hypotube 220 can be a single piece construction tubularmember. The hypotube 220 can have a proximal section 221 and a distalsection 222 with an inflation lumen 200 and a longitudinal axis definedtherethrough. The inflation lumen 200 of the hypotube 220 can compriseany suitable configuration, such as a substantially circularconfiguration as shown in FIG. 4.

In accordance with the disclosed subject matter, the distal section 222of the hypotube 220 can comprise a skive, which is a cut section of thehypotube that gradually reduces in dimension distally along its length.For example, as illustrated in FIGS. 1 and 2, the hypotube 220 can beskived at its distal section 222 with a stepped configuration. Thestepped skive in accordance with the disclosed subject matter canimprove the pushability (e.g., push force transmission) and resistanceto kinking (e.g., by reducing kink points) of the catheter by providinga smoother transition between the hypotube and the more distal cathetercomponents (e.g., the monolithic single-layer distal outer member asfurther discussed herein). The stepped skive can also provide improvedsupport for the proximal port 280 described herein.

In some embodiments of the disclosed subject matter, as depicted in FIG.2, the skive of the hypotube 220 has three distinct sections including afirst angled cut 420, an axial cut 440, and a second angled cut 460. Thehypotube 220 can reduce in cross-sectional dimension distally along thelength of the skive. The first angled cut 420 can be at the distal endof the hypotube 220 and the axial cut 440 can be disposed between thefirst angled cut 420 and the second angled cut 460 proximate theproximal end of the skive. The first angled cut 420 can come to a pointat the extreme distal end of the skive/hypotube, as depicted in FIG. 2,or the distal end of the hypotube can include a blunt end as depicted inFIG. 3A. Other similar stepped configurations are contemplated.

In some embodiments, the first angled cut 420 and second angled cut 460each can have a linear or straight angled configuration as depictedherein, or can be curved, such as a parabolic like curve. The firstangled cut 420 and the second angled cut 460 can have the same angle ofinclination or can have different angles of inclination. As depicted inFIG. 2, for purposes of illustration, the first angled cut 420 and thesecond angled cut 460 can be substantially parallel with each other. Inother embodiments, the first angled cut 420 extends at a first anglerelative the longitudinal axis of the hypotube 220 and the second angled460 cut extends at a second angle relative the longitudinal axis of thehypotube 220 such that the first angle is different from the secondangle. For example, but without limitation, angle 460 can be steeperthan angle 420. In some embodiments, the angle for 420 is about 0.020°and the angle for 460 is approx. 0.3°. Preferably, the angles should beshallow (e.g., close to 0) to provide improved force transmission andreduce the chance of kinking.

As embodied herein, the first angled cut 420, the axial cut 440, and thesecond angled cut 460 can have the same or varying lengths, although theoverall dimensions can preferably correspond with dimensions of themonolithic single-layer distal outer member 230 as described furtherbelow. For the purpose of illustration, FIGS. 3A and 3B depictschematics of the distal section of the hypotube 220 for a coronaryballoon dilation catheter, wherein the hypotube 220 has the first angledcut 420, the axial cut 440, and the second angled cut 460. In theexample of FIGS. 3A and 3B, the first angled cut 420 has an axial lengthG between about 20 mm and about 30 mm, preferably about 25 mm plus orminus about 2 mm, for example about 25 mm. The first angled cut 420 ofthis embodiment has a blunt end which can have a distal height H rangingbetween about 5% to about 25% of the outer diameter of the hypotube 220.In some embodiments, the height H can be about 0.0025 inches to about0.0065 inches, preferably about 0.0035 inches to about 0.0045 inches,for example about 0.0040 inches plus or minus 0.0005 inches.

As shown in FIG. 3A, the axial cut 440 can have an axial length Aranging between about 10 mm and about 40 mm, preferably about 25 mm plusor minus about 2 mm, for example about 25 mm. The axial cut 440 can havea height C, as depicted in FIG. 3A, that ranges between about 20% toabout 50% of the outer diameter of the hypotube 220. For example, theheight C ranges between about 0.0060 inches and about 0.0110 inches,preferably about 0.0065 inches to about 0.0075 inches.

For the purpose of illustration, FIG. 3B is a cross-section of FIG. 3Aalong the lines 3B-3B. FIG. 3B depicts the outside diameter Ø_(A) andthe inside diameter Ø_(B) of the hypotube 220. In accordance with someembodiments of the disclosed subject matter, the skived hypotube 220 canhave increased dimensions so as to form a thicker structure thanpreviously described. For example, an increased thickness dimension canfurther improve column strength, push and kink resistance, and providefor enhanced scaffold control. For example, the inside diameter Ø_(B) ofthe hypotube 220 can be about 0.0195 inches to about 0.0220 inches,preferably 0.0195 inches to about 0.0205 inches. The outside diameterØ_(A) of the hypotube 220 can be about 0.0260 inches to about 0.0285inches, preferably about 0.0275 inches to about 0.0285 inches. The wallthickness of hypotube 220 can be between about 0.0030 inches and about0.0090 inches, preferably about 0.0080 inches. FIG. 3B further depictsthe height C of the axial cut 440 in relation to the outside diameterØ_(A) and the inside diameter Ø_(B).

As illustrated in FIG. 3A, the second angled cut 460 can have an overallheight I when measured from a side of between about 50% to about 90% ofthe outer diameter of the hypotube 220, preferably about 85%. Forexample, the height I can about 0.021 inch for a 0.025 inch diameterhypotube. The second angled cut 460 can have a length S of about 95 mmto about 105 mm, preferably about 98 mm to about 102 mm, for exampleabout 100 mm. FIG. 3B further depicts the height C of the axial cut 440in relation to the outside diameter Ø_(A) and the inside diameter Ø_(B).

Additionally, an end of one or more cuts can be radiused for transitionpurposes. For example, and as depicted in FIG. 3A, a proximal end of thesecond angled cut 460 can comprise a curved or radiused portion. Thesecond angled cut 460 depicted herein includes a radius of approximately0.040 inches plus or minus about 0.010 inches. In the embodiment of FIG.3A, the overall axial length of the skive with respect to the firstangled cut 420, the axial cut 440, and the second angled cut 460 canrange from about 100 mm to about 200 mm. Additional suitable dimensionsof the skive are contemplated. Additional features of a skived hypotubecan be found in U.S. Patent Publication No. 2012/0303054, which isincorporated by reference herein in its entirety.

As depicted in FIG. 2 for purpose of illustration, the monolithicsingle-layer distal outer member 230 of the catheter 100 includes aguidewire lumen 210, 211 and an inflation lumen 201, 202 definedtherethrough. The inflation lumen 201, 202 of the monolithicsingle-layer distal outer member 230 is in fluid communication with theinflation lumen 200 of the hypotube 220. Furthermore, at least a portionof the distal section of the hypotube 220 is disposed within theinflation lumen 201 of the monolithic single-layer distal outer member230 with the inflation lumen 200 of the hypotube 220 in fluidcommunication with the inflation lumen 201 of the monolithicsingle-layer distal outer member 230. The inflation lumen 201 of themonolithic single-layer distal outer member 230 depicted hereincomprises a generally crescent configuration at a proximal sectionthereof and the hypotube 220 is inserted into the inflation lumen 201,as further discussed herein.

As embodied herein and as illustrated in FIG. 2, an exterior surface ofthe monolithic single-layer distal outer member 230 can define aproximal port 280. The proximal port 280 is spaced distally from theproximal end of the catheter 100. The proximal port 280 is configured toreceive a guidewire 260 within the guidewire lumen 210 of the monolithicsingle-layer distal outer member 230 and inner tubular member 240. Insome embodiments, the proximal port 280 is reinforced by the distalsection of the hypotube 220 by disposing the distal section of thehypotube 220 proximate the proximal port 280 of the monolithicsingle-layer distal outer member 230. In some embodiments, at least aportion of the axial cut 440 is disposed proximate to the proximal port280 of the guidewire lumen 210. The location of the proximal port 280can depend upon various factors, such as the size of the balloon 140, asfurther discussed herein. In some embodiments, second angled cut 460 isproximal the proximal port 280, the axial cut 440 begins proximal theproximal port 280 and continues distal of the port 280 and first angledcut 420 is located distal of proximal port 280 and extends into a regionwhere the monolithic single-layer distal outer member 230 and the innertubular member are coaxial.

For purpose of illustration and not limitation, FIG. 4 is across-section of the catheter 100 of FIG. 2 along the lines 4-4. Asdepicted in FIG. 4, the hypotube 220 at this section is a single lumenmember defining the inflation lumen 200 therethrough with a circularcross section. FIG. 5 is a cross-section of the catheter 100 of FIG. 2along the lines 5-5. In FIG. 5, the inflation lumen 201 of themonolithic single-layer distal outer member 230 includes a substantiallycircular cross section. The inflation lumen 200 of the hypotube 220 isfluidly connected to the lumen 201 of the monolithic single-layer distalouter member 230. As depicted in FIG. 5, the second angled cut 460 isdisposed within the inflation lumen 201 of the monolithic single-layerdistal outer member 230, as further discussed herein.

For purpose of illustration, FIG. 6 is a cross-section of the catheter100 of FIG. 2 along the lines 6-6. The monolithic single-layer distalouter member 230 at 6-6 includes a crescent like cross section for theinflation lumen 201. With respect to FIGS. 5 and 6, the inflation lumen201 of the monolithic single-layer distal outer member 230 transitionsfrom a circular cross section at FIG. 5 to a crescent like cross sectionat FIG. 6. The transition of the circular cross section of themonolithic single-layer distal outer member 230 to the crescent likecross section of the monolithic single-layer distal outer member 230allows for a smooth transition in flow, as described further herein. Thecrescent like cross section of inflation lumen 201 can provide for acatheter with a reduced profile as compared to a catheter having a roundinflation lumen at locations proximate the proximal port 280.

As depicted in the cross section of FIG. 6, the axial cut 440 can bedisposed at least partially in the crescent inflation lumen 201. Thespace around (e.g., above) the axial cut 440 can define the volume forinflation fluid flow. The corners of the crescent or “smiley”configuration can be rounded or otherwise provided in any suitableshape. The cross section also includes inner tubular member 240 andhaving guidewire lumen 210 and guidewire 260 disposed therein.

For purpose of illustration and not limitation, FIG. 7 is across-section of the catheter 100 of FIG. 2 along the lines 7-7. FIG. 7depicts a cross section of the monolithic single-layer distal outermember 230 in which the inflation lumen 201 has transitioned from thecrescent configuration to an annular configuration. The first angled cut420 interfaces with the monolithic single-layer distal outer member 230and is positioned adjacent and below, as depicted in FIG. 7, theguidewire lumen 210 as defined by inner tubular member 240 and havingguidewire 260 disposed therein. The inflation lumen 201 is generallycoaxial with the guidewire lumen 210.

Thus, as embodied herein and as shown in FIGS. 4-7, the inflation lumen200 of the hypotube 220 transitions from a circular cross section atsection 4-4 of FIG. 2, to a generally crescent or “smiley” configurationat section 6-6 of the inflation lumen 201 of the monolithic single-layerdistal outer member 230 and then ultimately to an annular cross sectionat section 7-7 and 8-8. However, the inflation lumen 201 can havealternative cross-sectional shapes as desired.

In accordance with the disclosed subject matter, the skive can serve asa male end section of the hypotube 220 and the inflation lumen 201 ofthe monolithic single-layer distal outer member 230 can serve as thefemale receiving end section. At least a portion of the stepped skive atthe distal end section of the hypotube 220 can be configured to bereceived within the inflation lumen 201 of the monolithic single-layerdistal outer member 230. The skive of hypotube 220 can be disposedwithin the crescent or smiley shaped inflation lumen to fluidly connectthe inflation lumen 200 of the hypotube 220 with the inflation lumen 201of the monolithic single-layer distal outer member 230. For example, andas embodied herein the skive portion of the hypotube 220 is disposedwithin the inflation lumen 201 of the monolithic single-layer distalouter member 230, as depicted in FIGS. 1 and 6. The axial cut 440 can“float” within inflation lumen 201 and/or interface with a portion of asurface of the inflation lumen 201 of the monolithic single-layer distalouter member 230. In alternative embodiments, at least the axial cut 440can be press fit with the inflation lumen 201 of the monolithicsingle-layer distal outer member 230. Furthermore, as embodied herein,the first angled cut 420 is inserted through the inflation lumen 201 ofthe monolithic single-layer distal outer member 230, as depicted in FIG.2. Accordingly, the skive can assist in joining and reinforcing thehypotube 220 with the monolithic single-layer distal outer member 230,while facilitating a smooth transition in flexibility and reduce kinkingof the catheter.

In accordance with the disclosed subject matter, the monolithicsingle-layer distal outer member 230 can be bonded to the hypotube 220.For example, the distal section of the hypotube 220 can have a roughenedor textured outer surface to enhance the bond with the monolithicsingle-layer distal outer member 230. The hypotube 220 can beconcentrically aligned within the monolithic single-layer distal outermember 230. Accordingly, the outer diameter or exterior surface of thehypotube 220 can be sized to fit concentrically within the interiorsurface of the monolithic single-layer distal outer member 230 at leastat a distal section of the hypotube 220. The hypotube 220 can be bondedto the monolithic single-layer distal outer member 230 along theroughened or textured portion, with the remainder of the hypotube (e.g.,including the skive) free of attachments to the monolithic single-layerdistal outer member 230. Alternatively, in some embodiments, thehypotube 220 can be bonded with the monolithic single-layer distal outermember 230 along the length of the hypotube 220 or at portions along thelength of the hypotube 220.

In some embodiments, the hypotube 220 can be free of any outer coatingor jacket, so as to have a bare exposed outer surface. In this manner, ahypotube 220 of larger cross section can be provided without increasingthe profile of the proximal shaft section 120 as compared to aconventional rapid exchange catheters with a coated or jacketedhypotube. For example, the reduction in thickness by omitting a coatingcan allow for a proportional increase in both the outer diameter andthus the inner diameter of the tubular member. Thus, the overall profileof the catheter along a proximal end section can remain the same, butthe dimensions of the inflation lumen therein can be increased. Theincrease in inner diameter can result in greater fluid flow forincreased inflation or deflation (e.g., decreased inflation anddeflation times) as compared to conventional catheters. In someembodiments, a thicker hypotube can be provided that can provideincreased strength and pushability without substantially effectingprofile and or inflation time as compared to known jacketed hypotubes.Further, the bare hypotube can also result in a better grip and areduction in kinking.

As embodied herein, the catheter shaft 110 includes a monolithic innertubular member 240 that defines the guidewire lumen 210, 211 configuredto slidably receive a guidewire 260 therein. As shown in FIG. 1 forillustration, the inner tubular member 240 can comprise one tube (i.e.,monolithic and/or zero-transition) such that the inner tubular member240 forms the tip 270. The zero-transition inner tubular member 240 canprovide continuous flexibility, direct force transfer, crossing ofchallenging anatomy with less force, and tactile feedback.

Thus, from the proximal end section to the distal end section, thecatheter 100 embodied herein transitions from a single lumen (inflationlumen) configuration in the proximal shaft section 120 to a coaxial duallumen (inflation lumen and guidewire lumen) configuration in the distalshaft section 130. The area proximate the skive of hypotube 220generally defines the juncture between the single lumen hypotube 220 andthe coaxial dual lumen distal shaft section 130.

As depicted in FIG. 1, balloon 140 can be coupled to the monolithicsingle-layer distal outer member 230 and is in fluid communication withthe inflation lumens 200, 201, and 202. For purpose of illustration andnot limitation, FIG. 9 is a cross-section of the catheter 100 of FIG. 1along the lines 9-9. As depicted in FIGS. 1 and 9, a balloon 140 issealingly secured to the monolithic single-layer distal outer member 230such that an interior of the balloon 140 is in fluid communication withinflation lumens 200, 201, and 202 and includes inner tubular member 240and guidewire 260 therein. The balloon 140 is coupled to the monolithicsingle-layer distal outer member 230 by at least one of bonding,adhesive, lap joint, and butt joint or by other suitable configurationsas known in the art, however, a lap joint Formed via heat bonding ispreferred.

As shown in FIG. 1 for illustration and not limitation, the balloon 140can have a proximal balloon shaft 145, a proximal cone portion 144, aproximal shoulder 147, a working length 143, a distal shoulder 146, adistal cone portion 142, and a distal balloon shaft 141. The balloon 140can be coupled to the distal outer member 230 and monolithic innertubular member 240 in any suitable manner. In some embodiments, theballoon 140 is coupled to the distal outer member 230 along alongitudinal length of the proximal balloon shaft 145 and coupled to themonolithic inner tubular member 240 along a longitudinal length of thedistal balloon shaft 141, as depicted in FIG. 1. For example, the distalballoon shaft 141 can have a distal seal portion 1247 coupled to themonolithic inner tubular member 240 and a proximal portion 1248 of thedistal balloon shaft free of attachment to the inner tubular member 240as shown in FIG. 12 for the purpose of illustration and not limitation.The length of the proximal portion 1248 of the distal balloon shaft freeof attachment can be at least about two times the inner diameter 1246 ofthe distal balloon shaft 141.

As embodied herein and shown in FIG. 12 for the purpose of illustrationand not limitation, the inner tubular member 240 can be a monolithicpiece that forms the tip 270 of the catheter. The tip 270 includes adistal exposed portion 272 and a proximal portion 273 along the lengthof the distal seal portion 1247 of the distal balloon shaft. In someembodiments, the length of the proximal portion 1248 of the distalballoon shaft is about 63% to about 67% the length of the tip 270.Furthermore, the length of the proximal portion 1248 of the distalballoon shaft can be about 30% to about 40% of the combined length ofthe distal balloon shaft 141 and the distal exposed portion 272 of thetip.

In some embodiments, the tip length 270 is less than about 5 mm(including the distal exposed portion 272 and the proximal portion 273).In some embodiments, the tip length can be about 3.0 mm to about 3.2 mmfor 2.5 mm to 3.5 mm balloons. As discussed herein, the tip can taperdistally and define a distal most tip 271 having an outer diameter of upto about 0.020 inches and inner diameter of about 0.015 inches minimum.

In some embodiments, the distal balloon shaft 141 can have inner andouter diameters that vary based on the size of the balloon: for 2.50 mmballoons, the inner diameter can be a minimum of 0.0220 inches and theouter diameter can be about 0.0290 inches; for 3.00 mm balloons, theinner diameter can be a minimum of 0.0220 inches and the outer diametercan be about 0.0325 inches; and for 3.5 mm balloons, the inner diametercan be a minimum of 0.0220 inches and the outer diameter can be about0.0325 inches.

In some embodiments, the distal balloon shaft 141 can have a trim length1260 prior to sealing to the inner tubular member 240 of about 2.8 mm toabout 3.0 min. The distal seal portion 1247 of the distal balloon shaftcan have a length of about 1.2 mm. The proximal portion 1248 of thedistal balloon shaft free of attachment to inner tubular member 240 canhave a length of about 2.0 mm.

The balloon cone length can vary based on the size of the balloon. Forexample, for 2.5 mm to 3.00 mm diameter balloons (of any length), theballoon cone length can be about 3 mm. For 3.5 mm diameter (of anylength), the balloon cone length can be about 4 mm.

Inner tubular member 240 including tip 270 and balloon 140configurations in accordance with the disclosed subject matterunexpectedly provide for improved trackability, allowing the catheter toadvance further within the vascular system of a patient. For example,the length of the proximal portion 1248 of the distal balloon shaft freeof attachment to the inner tubular member 240 in accordance with thedisclosed subject matter can provide for centering of the catheter(e.g., a coaxial position system) when traversing a bend in the vesselsystem, providing reduced stent damage as compared to known cathetersdue to contact with the side of the vessel (e.g., calcified lesions).Furthermore, known catheter systems having a distal balloon shaftentirely bonded to the inner tubular member and/or tip can haveincreased stiffness, which can reduce the trackability of the distalportion of the catheter as compared to catheters in accordance with thedisclosed subject matter.

In accordance with the disclosed subject matter, the distal balloonshaft 141 of the balloon 140 can be coupled to the inner tubular member240 in a plurality of suitable ways. For example, the distal balloonshaft 141 can be fusion bonded to the inner tubular member 240, forexample, by applying heat to at least a portion of the area of overlap.For illustration and without limitation, electromagnetic energy, such asthermal, laser, or sonic energy can be applied to the distal balloonshaft 141 to bond at least a portion of the distal balloon shaft 141 tothe inner tubular member 240. Heating the distal balloon shaft 141 cancause the polymeric material of the distal balloon shaft 141 to soften,or melt and flow, providing a distal seal portion 1247 with a taperedconfiguration as shown in FIG. 12.

In some embodiments, a heat shrink tubing (not shown) can be positionedaround the outside of the distal balloon shaft 141, which can have atrim length of about 10 mm to about 15 mm prior to melt bonding. Theheat shrink tubing, also referred to as a “heat shrink sleeve,” can becomposed of a polymeric material configured to shrink when exposed toheat. U.S. Pat. No. 7,951,259, which is hereby incorporated by referencein its entirety, discloses the use of a heat shrink sleeve infabricating a catheter with a flexible distal end. The heat shrinktubing, when heated, shrinks and exerts an inward radial force on thedistal balloon shaft 141. With the polymer of the distal balloon shaft141 in a molten or softened state, the diameter of the distal balloonshaft 141 can be reduced by the force exerted by the heat shrink tubing.After the balloon 140 is cooled, the heat shrink tubing can be removed.Heating can be accomplished, for example, by laser heating (e.g., usinga CO₂ laser), contact heating (e.g., using aluminum nitride, resistance,RF), hot air, resistance heating, induction heating or the like. Asembodied herein, for purposes of illustration and not limitation, asolid state laser can be used to heat the shrink tubing and soften thedistal balloon shaft 141. As a result, a portion of the outer surface ofthe distal balloon shaft 141, in its softened or molten state, can bebonded to the inner tubular member 240. Other catheter connections, suchas the proximal balloon shaft 145 to the distal outer member 230 (e.g.,via lap joint with proximal balloon shaft 145 over the distal outermember 230), can be formed using the fusion bonding methods describedherein.

In some embodiments, the exposed portion 272 of the tip can be taperedor rounded as shown in FIG. 12 during the same laser bonding process asforming the bond between the distal balloon shaft 141 and the innertubular member 240 by traversing the laser along the length of the tip270 and allowing the molten material to flow distally. The tapered tipcan provide improved maneuverability to traverse tortuous anatomy. Thedistal balloon shaft 141 provides an area to seal 1247 the distal end ofthe balloon 140 to the inner tubular member 240. In some embodiments, asmaller length of the seal can provide improved flexibility to thedistal section of the catheter but still provide suitable tensilestrength. A smaller length of the seal can also reduce heat-induceddamage to the balloon cone during the heat bonding process (which couldresult in rupture) by increasing the distance between the location ofthe seal and the balloon cone section. According to some embodiments ofthe disclosed subject matter, the distal balloon shaft 141 can benon-milled. Forming the balloon 140 with a distal seal portion 1247coupled to the inner tubular member 240 and a proximal portion 1248 freeof attachment to the inner tubular member 240 according to the disclosedsubject matter can improve catheter trackability through tortuousvasculature or the like.

As depicted in FIG. 1 for the purpose of illustration and notlimitation, the balloon 140 can comprise as a single layer of polymermaterial. For example, the balloon 140 can comprise a wide variety ofsuitable polymer materials, for example, nylons, co-polyamides such aspolyether block amides (for example commercially available as PEBAX®),polyester, co-polyester, polyurethane, polyethylene, or the like. Theballoon 140 can be formed of a polymeric material which is compatiblewith the material forming the outer surface of the shaft, to allow forfusion bonding, although the balloon 140 can alternatively oradditionally be adhesively bonded to the shaft. In some embodiments, theballoon 140 can comprise a single layer of polyether block amide (e.g.,commercially available as PEBAX®). The polyether block amide can haveany suitable Shore durometer hardness, such as between about 63 D and 72D, for example about 72 D.

Alternatively, multilayered balloons can be used. For example, theballoon 140 can have a first layer made of a first polymer materialhaving a first Shore durometer hardness, and a second layer made of asecond polymer having a second Shore durometer hardness. In someembodiments, the first Shore durometer hardness can be greater than thesecond Shore durometer hardness, and the first layer can be an outerlayer relative to the second layer. For example, the balloon 140 canhave a first outer layer of polyether block amide (e.g., commerciallyavailable as PEBAX®) having a Shore durometer hardness of between about55 D and about 63 D and a second inner layer of polyether block amidehaving a Shore durometer hardness of between about 70 D and about 72 D.In some embodiments, the balloon 140 has a first outer layer of PEBAX®72 D and a second inner layer of PEBAX® 63 D. Details of suitablemultilayer balloons are described in U.S. Pat. No. 7,828,766, U.S.application Ser. No. 12/897,202, and U.S. application Ser. No.13/680,299, the contents of each of which are herein incorporated byreference in their entirety.

In accordance with the disclosed subject matter, the balloon can havewings and be folded as known in the art. For example, the balloon canhave three folds for 2.5 mm to 3.5 mm diameter balloons. The balloonfolds can improve the uniformity of stent or scaffold deployment.

As embodied herein, the balloon 140 can be a relatively high rupturepressure, non-compliant balloon, which in some embodiments has a rupturepressure of about 20 atm to about 30 atm or more, such that the balloon140 can be inflated in the patient during a procedure at relatively highworking pressure of about 18 atm. The rated burst pressure of acatheter, calculated from the average rupture pressure, is the pressureat which 99.9% of the catheters can be pressurized to without rupturing,with 95% confidence. Generally, a balloon is inflated in the patientduring a procedure at working pressure of about 8 atm to about 18 atm,preferably about 10 atm to about 18 atm. In some embodiments, thecatheter with balloon 140 has a rated burst pressure of about 14 atm toabout 25 atm. In embodiments having a single layer balloon 140 of PEBAX®72 D, the rated burst pressure can be at least about 16 atm. Inembodiments having a balloon with a first outer layer of PEBAX® 72 D anda second inner layer of PEBAX® 63 D, the rated burst pressure can beabout 18 atm and the nominal pressure can be about 10 atm. The balloon140 can be any suitable size known in the art, e.g., 2.00, 2.25, 2.50,2.75, 3.00, 3.25, 3.50, or 4.00 mm diameter.

Additional suitable materials, configurations, and methods ofmanufacture of the balloon 140 are provided in U.S. Pat. Nos. 7,074,206,and 8,052,638, the contents of each of which are hereby incorporated byreference in their entirety. Additional features proximate the balloon140 can include markers (e.g., made of platinum/iridium and located bothends of the working length of the balloon), stents or scaffolds, and anatraumatic tip. Examples of such features and additional featuresinclude those described in U.S. Pat. No. 7,862,541; U.S. applicationSer. No. 12/983,504; U.S. Pat. No. 7,549,975; U.S. application Ser. No.12/468,745; U.S. Pat. No. 6,964,750; U.S. application Ser. No.11/455,382; U.S. Pat. Nos. 7,833,597; 7,322,959; 7,303,798; U.S.application Ser. No. 11/775,480; U.S. application Ser. No. 12/945,566;U.S. Publication 2010/0285085; U.S. Publication No. 2010/0189876; U.S.Pat. No. 6,923,822; U.S. application Ser. No. 11/189,536; U.S.Publication No. 2009/0036829; U.S. Publication No. 2007/0021772; U.S.application Ser. No. 11/241,936; and U.S. application Ser. No.14/212,966, the contents of each of which are herein incorporated byreference in their entirety.

In accordance with the disclose subject matter, the balloon 140 can havea stent or scaffold (not shown) mounted thereon for stent or scaffolddelivery applications. The stent or scaffold can be made of any suitablematerial. For example, the scaffold can be bioresorbable and can be madeof, for example, Poly(L-lactide) (PLLA). Alternatively, the stent cancomprise a metal, e.g., a cobalt chromium alloy (e.g., L-605 comprisingCo—Cr—W—Ni). For bioresorbable scaffolds, markers, e.g., comprisingplatinum, such as beads at the ends of the scaffold can be used, whichcan help in positioning the scaffold during delivery. The scaffold (orstent) can include one or more coatings, for example a bioresorbablecoating, for example of Poly (D, L-lactide) (PDLLA) can be used.

The stent or scaffold can have any suitable dimensions (e.g., having adiameter of 2.5, 3.0, or 3.5 mm) and be any suitable length, e.g., 8,12, 15, 18, 23, or 28 mm. The stent or scaffold can have any suitableconfiguration as known in the art. The inner tubular member can includemarkers along its longitudinal length. For example, the inner tubularmember can have a distal marker 148 and a proximal marker 149 along itslength, as shown in FIG. 1. In some embodiments, the middle of themarkers are longitudinally aligned with the ends of stent or scaffold toimprove placement of the stent or scaffold at the target site duringtreatment. The markers can be about 1.0 mm wide for 8 mm to 28 mm stentsor scaffolds. The shaft (e.g., the hypotube) can also include proximalmarkers 95 cm and 105 cm proximal of the distal tip.

As embodied herein, the stent or scaffold can include a drug and/or orpolymer coating as known in the art.

As depicted in FIG. 1 for purpose of illustration and not limitation, anadapter 225 (e.g., single arm) and a strain relief can be provided atthe proximal end of the catheter 100 for access to the inflation lumens200, 201, 202 collectively, and can be configured for connecting to aninflation fluid source (not shown). The balloon 140 can be provided at adistal end of the catheter and in fluid communication with the inflationlumens 200, 201, 202. The distal end of the catheter can be advanced toa desired region of a body lumen in a conventional manner and balloon140 inflated to perform a medical procedure, such as to dilate astenosis and/or deliver a stent, scaffold, or the like. The catheter 100is then withdrawn or repositioned for another procedure. FIG. 1illustrates the balloon 140 in an inflated configuration.

In accordance with the disclosed subject matter, the catheter componentscan comprise a variety of suitable materials. For example, the hypotube220 can be a more rigid material than the material of the distal outermember 230. In some embodiments, the hypotube 220 can be a relativelyhigh stiffness material including a metal, such as but not limited tostainless steel (e.g., 304), although a high durometer polymer can beused. The distal outer member 230, coupled to the hypotube 220, can bemore flexible than the hypotube 220 and can comprise a more flexiblematerial. In some embodiments, the distal outer member 230 can be asingle layer and can comprise a polyether block amide (e.g.,commercially available as PEBAX®) having as shore Durometer hardness ofabout 72 D. Alternatively, the distal outer member 230 can compriseother polymers and/or can be a multilayer member made of one or morepolymers, such as different Shore durometer hardness of polyamide orpolyether block amides.

As embodied herein, the monolithic inner tubular member 240 can be asingle layer or multilayer member made of one or more polymericmaterials. For example, the inner tubular member 240 can comprise outer,inner and intermediate layers. The layers can be made of any suitablematerials. For example, the outer layer can comprise a polyether blockamide and/or nylon, the inner layer can comprise a lubricious polymer,and the intermediate layer can comprise a tie layer to bond the outerlayer and the inner layer. In some embodiments, the outer layercomprises a polyether block amide, the inner layer comprises highdensity polyethylene (HDPE), and the intermediate layer comprises anethylene acrylic acid adhesive polymer commercially available asPrimacor®. The inner tubular member 240 can have any suitabledimensions, such as an outer diameter of about 0.0200 inches to about0.0225 inches and an inner diameter of about 0.016 inches to about0.0165 inches.

In accordance with the disclosed subject matter, a rapid exchangeproximal port 280 can be formed in the distal outer member 230 at anysuitable location along the length of the catheter using any techniqueknown in the art. For example, an opening can be formed in the side wallof the distal outer member 230 and the inner tubular member 240 can beinserted through the opening to extend distally within the catheter(e.g., through the distal outer member and balloon). A mandrel orpressurizing fluid can be provided within the guidewire lumen 210 of theinner tubular member 240 to maintain the round shape of the guidewirelumen 210 during bonding, and optionally a shrink wrap can be providedover the distal outer member 230 proximate the opening. The distal outermember 230 can be fusion bonded, for example by heating with a laser, tothe inner tubular member 240 within the interior of the distal outermember 230. The crescent shape of the inflation lumen 201, as shown inFIG. 10B for illustration, of the distal outer member 230 can be formedduring the heating process by positioning a crescent shaped mandrelwithin the distal outer member 230 proximate the port. The heatingprocess can provide a temperature sufficient to soften or melt thematerials of the distal outer member 230 and the inner tubular member240 to define the lumens therein. Shrink wrap material can be used tomaintain the outer shape and dimension of the distal outer member 230 bythe fusion process. The mandrel and shrink wrap can then be removedafter the fusion or heating process is complete.

For purpose of illustration and not limitation, FIGS. 10A and 10B depictcross-sections of the distal outer member 230 during manufacture. FIG.10A depicts the cross section of the distal outer member 230 and innertubular member 240 of a coaxial configuration, where the guidewire lumen210 is concentric with the inflation lumen 201, similar to FIG. 8. FIG.10B depicts a cross-section from the distal outer member 230 after themelting or fusion process depicting the inflation lumen 201 defined by acrescent mandrel. The dual lumen configuration of FIG. 10B can be formedas described above or by alternative techniques known in the art. Forexample, the distal outer member 230 can be molded to include a duallumen member extending at least a length thereof for purpose of strengthand transition from the proximal end section to the distal end section.

As embodied herein, after necking as described above, the catheter canbe subsequently assembled, at least by sealingly securing a balloon 140to a distal end of the distal outer member 230 via heat bonding, asdescribed herein, such that the balloon 140 has an interior in fluidcommunication with the inflation lumen 202 of the distal outer member230. Portions of the catheter can be coated as known in the art, forexample with a hydrophilic coating of poly(ethylene oxide) (PEO).

Catheters in accordance with the disclosed subject matter can be of anysuitable dimensions, but preferably the shaft can have a reducedprofile. For example, the proximal portion of the shaft can have amaximum diameter of about 0.0480 inches, and the distal outer member canhave a diameter of 0.037 inches to about 0.040 inches. The crossingprofile can be about 0.060 inches (for a 3.0×18 mm balloon) and the tipentry profile can be about 0.021 inches. The working length of thecatheter can be about 145 cm.

EXAMPLE 1

The burst pressure of balloon catheters having various sized balloonsprepared in accordance with the disclosed subject matter were tested inaccordance with IS010555-4:2013, and the results are shown in Table 1.The balloon catheters included a monolithic single-layer distal outermember 230 comprising PEBAX® 72 D necked along its entire length and ahypotube comprising a skive defined by a first angled cut, an axial cut,and a second angled cut as described herein above. As demonstrated bythe data in Table 1, balloon catheters in accordance with the disclosedsubject matter provide burst pressures significantly above theacceptance criteria (i.e., 16 atm), which is used for typical inflationpressures in medical procedures. For example, for 2.5 mm, 3.0 mm, and3.5 mm diameter balloons, the average burst pressure was 41 atm, 44 atm,and 41 atm, respectively.

TABLE 1 Balloon Size Quantity Avg. Standard Min Max (diameter × length)Tested BP Deviation BP BP 2.5 mm × 28 mm 17 41 0.8 40 42 2.5 mm × 28 mm17 44 0.0 44 44 2.5 mm × 28 mm 16 41 0.7 10 42

While the disclosed subject matter is described herein in terms ofcertain preferred embodiments, those skilled in the art will recognizethat various modifications and improvements can be made to the disclosedsubject matter without departing from the scope thereof. Moreover,although individual features of one embodiment of the disclosed subjectmatter can be discussed herein or shown in the drawings of the oneembodiment and not in other embodiments, it should be apparent thatindividual features of one embodiment can be combined with one or morefeatures of another embodiment or features from a plurality ofembodiments.

In addition to the specific embodiments claimed below, the disclosedsubject matter is also directed to other embodiments having any otherpossible combination of the dependent features claimed below and thosedisclosed above. As such, the particular features presented in thedependent claims and disclosed above can be combined with each other inother manners within the scope of the disclosed subject matter such thatthe disclosed subject matter should be recognized as also specificallydirected to other embodiments having any other possible combinations.Thus, the foregoing description of specific embodiments of the disclosedsubject matter has been presented for purposes of illustration anddescription. It is not intended to be exhaustive or to limit thedisclosed subject matter to those embodiments disclosed.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the method and system of thedisclosed subject matter without departing from the spirit or scope ofthe disclosed subject matter. Thus, it is intended that the disclosedsubject matter include modifications and variations that are within thescope of the appended claims and their equivalents.

The invention claimed is:
 1. A balloon catheter comprising: an outershaft including a hypotube and a monolithic single-layer distal outermember of polymer material, the outer shaft having an inflation lumendefined therethrough, wherein the monolithic single-layer distal outermember is necked to a reduced diameter along an entire length thereofwith the polymer material consisting essentially of polymer chains in alinear orientation, wherein a proximal end of the monolithicsingle-layer distal outer member is coupled to the hypotube, and whereina distal section of the hypotube comprises a skive defined by a firstangled cut, an axial cut, and a second angled cut; a balloon in fluidcommunication with the inflation lumen, the balloon having a proximalballoon shaft coupled to a distal end of the monolithic single-layerdistal outer member; and a monolithic inner tubular member having aguidewire lumen defined therethrough, the monolithic inner tubularmember extending distally from a proximal port in the monolithicsingle-layer distal outer member through the balloon to form a tip. 2.The balloon catheter of claim 1, wherein the balloon further comprises adistal balloon shaft having an inner diameter, the distal balloon shafthaving a distal seal portion coupled to the monolithic inner tubularmember and a proximal portion free of attachment to the monolithic innertubular member.
 3. The balloon catheter of claim 2, wherein the lengthof the proximal portion of the distal balloon shaft is at least twotimes the inner diameter of the distal balloon shaft.
 4. The ballooncatheter of claim 1, wherein the monolithic single-layer distal outermember comprises polyether block amide.
 5. The balloon catheter of claim4, wherein the polyether block amide has a Shore durometer hardness of63 D to 72 D.
 6. The balloon catheter of claim 5, wherein the polyetherblock amide has a Shore durometer hardness of 72 D.
 7. The ballooncatheter of claim 1, wherein the reduced diameter comprises a firstreduced outer diameter and a first reduced inner diameter along aproximal portion of the monolithic single-layer distal outer member anda second reduced outer diameter and a second reduced inner diameteralong the distal end of the monolithic single-layer distal outer member.8. The balloon catheter of claim 7, wherein the first reduced outerdiameter is 0.038 inches to 0.039 inches, the first reduced innerdiameter is 0.029 inches to 0.0295 inches, the second reduced outerdiameter is 0.034 inches to 0.035 inches, and the second reduced innerdiameter is 0.029 inches to 0.0295 inches.
 9. The balloon catheter ofclaim 8, wherein the length of the distal end of the monolithicsingle-layer distal outer member is 1.0 mm to 1.2 mm.
 10. The ballooncatheter of claim 1, wherein the first angled cut has a length of 25 mm,the axial cut has a length of 25 mm, and the second angled cut has alength of 100 mm.
 11. The balloon catheter of claim 1, wherein the axialcut has a height of 0.0065 inches to 0.0075 inches.
 12. The ballooncatheter of claim 1, wherein the first angled cut defines a distal edgeheight of 0.0035 inches to 0.0045 inches.
 13. The balloon catheter ofclaim 1, wherein a proximal section of the hypotube has an outerdiameter of 0.0275 inches to 0.0285 inches and an inner diameter of0.0195 inches to 0.0205 inches.
 14. The balloon catheter of claim 1,further comprising a scaffold mounted on the balloon.
 15. The ballooncatheter of claim 14, wherein the scaffold is bioresorbable.
 16. Theballoon catheter of claim 1, wherein the monolithic single-layer distalouter member has a double wall thickness of 0.0085 inches to 0.01inches.
 17. A method of making a balloon catheter, comprising: necking atubular member of polymer material to form a monolithic single-layerdistal outer member necked along an entire length thereof with thepolymer material consisting essentially of polymer chains in a linearorientation; providing a hypotube; coupling a proximal end of themonolithic single-layer distal outer member to the hypotube to form anouter shaft having an inflation lumen defined therethrough; providing aballoon in fluid communication with the inflation lumen, the balloonhaving a proximal balloon shaft; coupling the proximal balloon shaft toa distal end of the monolithic single-layer distal outer member; andproviding a monolithic inner tubular member having a guidewire lumendefined therethrough, the monolithic inner tubular member extendingdistally from a proximal port in the monolithic single-layer distalouter member through the balloon to form a tip.
 18. The method of claim17, wherein the balloon further comprises a distal balloon shaft havingan inner diameter, and further comprising coupling a distal seal portionof the distal balloon shaft to the monolithic inner tubular member andallowing a proximal portion of the distal balloon shaft to be free ofattachment to the monolithic inner tubular member.
 19. The method ofclaim 18, wherein the length of the proximal portion of the distalballoon shaft is at least two times the inner diameter of the distalballoon shaft.
 20. The method of claim 17, wherein the tubular member isnecked from a first outer diameter of 0.045 inches to a first reducedouter diameter of 0.038 inches to 0.039 inches and from a first innerdiameter of 0.033 inches to a first reduced inner diameter of 0.029inches to 0.0295 inches along a proximal portion of the monolithicsingle-layer distal outer member.
 21. The method of claim 17, whereinthe tubular member is necked from a first outer diameter of 0.045 inchesto a second reduced outer diameter of 0.034 inches to 0.035 inches andfrom a first inner diameter of 0.033 inches to a second reduced innerdiameter of 0.029 inches to 0.0295 inches along the distal end of themonolithic single-layer distal outer member.
 22. The method of claim 17,wherein the length of the distal end of the monolithic single-layerdistal outer member is 1.0 mm to 1.2 mm.
 23. The method of claim 17,further comprising mounting a bioresorbable scaffold on the balloon. 24.The method of claim 17, wherein the monolithic single-layer distal outermember has a double wall thickness of 0.0085 inches to 0.01 inches.